This invention relates to a valve and more particularly to a valve which may be used to inject fluids into or sample fluid from a process fluid stream flowing in a tube or pipe such as that which might occur in a manufacturing process, for example, a process stream in a continuous polymerization line for the manufacture of thermoplastic polymer.
The prior art in the field of valve design and fabrication teaches a number of valves which are useful for the regulation of fluid transfer to and from a variety of manufacturing operations. However, in certain kinds of manufacture, for example the production of thermoplastic polymers, the materials of manufacture are susceptible to degradation during periods in which they are not being actively processed, for example, during a period when such materials might be held up within a valve when the valve is temporarily closed.
It is, therefore, an object of this invention to provide a valve which may be used for injecting fluid additives into or sampling fluid from a flowing stream in a manufacturing process, in which the valve closure means is located in the flowing process stream.
It is another object of this invention to provide a valve which may be installed easily in tubing or piping used in a manufacturing process, for example in a continuous polymerization line for the manufacture of thermoplastic polymer.
It is another object of this invention to provide a valve which may be purged by a cleaning fluid with the closure means of the valve in the closed position, located in a flowing process stream.
It is another object of this invention to provide a valve which may be partially disassembled for cleaning without shutting down the manufacturing process in which the valve operates.
It is yet another object of this invention to provide a valve having sealing seats which may be removed from the valve body for cleaning.